Captopril In Pharmaceutical Formulations Research Articles

Introducing hierarchical hollow MnO2 microspheres as nanozymes for colorimetric determination of captopril.

A simple sensor was developed for the colorimetric determination of captopril (CPT). Herein, hierarchical hollow MnO2 microspheres (HH-MnO2) were applied as nanozymes with peroxidase-mimetic activity. Free cation radicals with a strong absorption signal (λmax at 653nm) were generated via a redox reaction between 3, 3', 5, 5'-tetramethylbenzidine (TMB) and HH-MnO2. Captopril could successfully prevent the generation of blue-colored free cation radicals. The influence of CPT concentration on the absorption of the generated radicals was monitored by UV-Vis spectroscopy. The corresponding linear concentration range was from 1.0 to 30.0μgmL-1 (4.6-138.1μmolL-1), and the detection limit was found to be 0.26μgmL-1 (1.2μmolL-1). As a practical usage, the developed sensor was effectively utilized to measure the content of CPT in pharmaceutical formulations.

Recent Progress in the Analysis of Captopril Using Electrochemical Methods: A Review

Background:Captopril is the synthetic dipeptide used as an angiotensin converting enzyme inhibitor. Captopril is used to treat hypertension as well as for the treatment of moderate heart failure. Analytical instrumentation and methodology plays an important role in pharmaceutical analysis.Methods:This review presents some important applications of electrochemical modes used for the analysis of captopril. So far captopril has been analyzed by using different bare and modified working electrodes with a variety of modifiers from organic and inorganic materials to various types of nano particles/materials.Results:This paper presents some of the methods which have been published in the last few years i.e. from 2003 to 2016. This review highlights the role of the analytical instrumentation, particularly electrochemical methods in assessing captopril using various working electrodes.Conclusion:A large number of studies on voltammetry noted by means of various bare and modified electrodes. Among all of the published voltammetric methods, DPV, SWV, CV and miscellaneous modes were trendy techniques used to analyze captopril in pharmaceutical formulations as well as biological samples. Electrodes modified with nanomaterials are promising sensing tools as this showed high sensitivity, good accuracy with precision as well as selectivity. In comparison to chromatographic methods, the main advantages of electrochemical methods are its cheaper instrumentation, lower detection limit and minimal or no sample preparation.

A Novel Use of 3-Methyl-2-Benzothiazolinone Hydrazone Hydrochloride Monohydrate for Kinetic Spectrophotometric Determination of Captopril in Pharmaceutical Formulations

A new, simple and sensitive kinetic spectrophotometric method has been proposed for the determination of captopril (CPT) in pharmaceutical formulations. The method is based on oxidation of 3-methyl-2-benzothiazolinone hydrazone hydrochloride monohydrate (MBTH) by ferric chloride followed by its coupling with the drug to form green-yellow colored product with absorbance maximum at 395nm. The concentration of CPT was calculated using the calibration equation for the rate data and fixed time methods. The linearity range was found to be 0.5–22.5 μg mL-1 for each method. The correlation coefficients were 0.9994 and 0.9971 for rate data and fixed time methods respectively. The proposed methods were applied successfully for the determination of CPT in pharmaceutical formulations. Statistical comparison of the results shows that there is no significant difference between the proposed and official methods.

A Novel Use of 3-Methyl-2-Benzothiazolinone Hydrazone Hydrochloride Monohydrate for Kinetic Spectrophotometric Determination of Captopril in Pharmaceutical Formulations

A new, simple and sensitive kinetic spectrophotometric method has been proposed for the determination of captopril (CPT) in pharmaceutical formulations. The method is based on oxidation of 3-methyl-2-benzothiazolinone hydrazone hydrochloride monohydrate (MBTH) by ferric chloride followed by its coupling with the drug to form green-yellow colored product with absorbance maximum at 395nm. The concentration of CPT was calculated using the calibration equation for the rate data and fixed time methods. The linearity range was found to be 0.5–22.5 μg mL-1for each method. The correlation coefficients were 0.9994 and 0.9971 for rate data and fixed time methods respectively. The proposed methods were applied successfully for the determination of CPT in pharmaceutical formulations. Statistical comparison of the results shows that there is no significant difference between the proposed and official methods.

Ruthenium Hexacyanoferrate (III) Modified Glassy Carbon Electrode for Determination of Captopril

AbstractA glassy carbon electrode modified with a ruthenium (III) hexacyanoferrate film was investigated for the determination of captopril in pharmaceutical formulations. The RuOHCF film was deposited on the surface of the electrode after applying 50 successive cycles and subsequent stabilization in a mixture of NaNO3 0.50 mol L−1+HCl 0.050 mol L−1 used as supporting electrolyte. The main processes responsible for the redox electrode response are attributed to the system RuII/RuIII/RuIV, and appeared at −0.080, 0.86 and 1.01 V (vs. SCE). The redox process at −0.080 V was selected for the determination of captopril in the present study, once it provided higher sensibility and occurs in a lower potential than the other ones which can prevent interferences. The experimental parameters used in the determination of the analyte, using differential pulse voltammetry were optimized: pulse amplitude: 50 mV, scan rate: 5 mV s−1 and potential window: −0.5 to 0.2 V (vs. SCE). The analytical application of the sensor in real samples demonstrated a linear range between 0.060 and 0.80 µmol L−1 (r=0.998) with a detection limit of 0.047 µmol L−1. A mechanism based on co‐precipitation of captopril and the Ru (III) complex in the film is presented once the signal of the RuII/III redox couple decreases with increasing the analyte concentration. Recoveries of 99 to 100 % were achieved in pharmaceutical samples and the proposed procedure agreed with the HPLC official method within 95 % confidence level, according to the t‐Student test.

Nitroprusside as a Novel Reagent for Flow Injection Spectrophotometric Determination of Captopril

ABSTRACTA novel flow injection system for the determination of captopril in pharmaceutical formulations is described. Nitroprusside was employed as a new, nontoxic reagent. Captopril reacted with nitroprusside in basic solution to yield a red chromophore with maximum absorbance at 521 nm. The calibration relationship was linear for concentrations from 3.0 × 10−6 to 1.0 × 10−3 mol L−1 with a limit of detection of 1.0 × 10−6 mol L−1. The recoveries from captopril tablets were between 99.7 and 102.3%. The sampling frequency was 50 h−1 and the relative standard deviation was estimated to be 1.0% for 5.0 × 10−4 mol L−1 captopril. A paired t-test showed that analysis of tablets by the flow procedure and a potentiometry provided similar results at the 95% confidence level.

Development of a new procedure for the determination of captopril in pharmaceutical formulations employing chemiluminescence and a multicommuted flow analysis approach.

This paper describes a new technique for the determination of captopril in pharmaceutical formulations, implemented by employing multicommuted flow analysis. The analytical procedure was based on the reaction between hypochlorite and captopril. The remaining hypochlorite oxidized luminol that generated electromagnetic radiation detected using a homemade luminometer. To the best of our knowledge, this is the first time that this reaction has been exploited for the determination of captopril in pharmaceutical products, offering a clean analytical procedure with minimal reagent usage. The effectiveness of the proposed procedure was confirmed by analyzing a set of pharmaceutical formulations. Application of the paired t-test showed that there was no significant difference between the data sets at a 95% confidence level. The useful features of the new analytical procedure included a linear response for captopril concentrations in the range 20.0-150.0 µmol/L (r = 0.997), a limit of detection (3σ) of 2.0 µmol/L, a sample throughput of 164 determinations per hour, reagent consumption of 9 µg luminol and 42 µg hypochlorite per determination and generation of 0.63 mL of waste. A relative standard deviation of 1% (n = 6) for a standard solution containing 80 µmol/L captopril was also obtained.

Determination of captopril using selective photoluminescence enhancement of 2-mercaptopropionic modified CdTe quantum dots

A photoluminescent probe for the determination of captopril is proposed based on the enhancement of luminescence from 2-mercaptopropionic modified CdTe quantum dots (2-MPA-CdTe QDs). Under optimum conditions, the calibration model (the Langmuir binding isotherm) was linear up to 4.8 × 10−4 mol L−1 with equilibrium binding constant of 3.2 × 104 L mol−1 and limit of detection (xb + 3 sb) of 2.7 × 10−7 mol L−1 (59 ng mL−1). The approach was tested in the determination of captopril in pharmaceutical formulations and the results were in agreement with the ones obtained using reference method. The possible mechanism of interaction is also investigated by Raman and electronic absorption spectroscopy and dynamic light scattering.

A surface plasmon resonance sensing method for determining captopril based on in situ formation of silver nanoparticles using ascorbic acid

A new method has been proposed to sensitive detection of captopril based on surface plasmon resonance band of silver nanoparticles (AgNPs). The stable and well-dispersed AgNPs with strong plasmon resonance signal were synthesized in situ using a simple and rapid procedure by applying ascorbic acid as reducer and sodium dodecyl sulfate as stabilizer, at room temperature. It was found that, the decreasing of AgNPs plasmon absorbance is proportional to the concentration of captopril which allows the spectrophotometric sensing of this compound. The presented method is capable of determining captopril over a range of 0.20–2.75μmolL−1 with a limit of detection 0.07μmolL−1. The relative standard deviation for eight replicate measurements of 1.00 and 2.50μmolL−1 of captopril was 2.37% and 1.02%, respectively. The method was applied to the determination of captopril in pharmaceutical formulations with satisfactory results, which were in agreement with those of the official method.

Spectrophotometric method for the determination of Captopril in pharmaceutical formulations

A simple, rapid and sensitive spectrophotometric method has been developed for the determination of captopril in aqueous solution. The method is based on reaction of captopril with 2,3-dichloro 1,4- naphthoquinon(Dichlone) in neutral medium to form a stable yellow colored product which shows maximum absorption at 347 nm with molar absorptivity of 5.6 ×103 L.mole-1. cm-1. The proposed method is applied successfully for determination of captopril in commercial pharmaceutical tablets.

Spectrophotometric method for the determination of Captopril in pharmaceutical formulations

A simple, rapid and sensitive spectrophotometric method has been developed for the determination of captopril in aqueous solution. The method is based on reaction of captopril with 2,3-dichloro 1,4- naphthoquinon(Dichlone) in neutral medium to form a stable yellow colored product which shows maximum absorption at 347 nm with molar absorptivity of 5.6 ×103 L.mole-1. cm-1. The proposed method is applied successfully for determination of captopril in commercial pharmaceutical tablets.

Permanganate–bromide–silver nanoparticles as a new chemiluminescence system and its application to captopril determination

A novel chemiluminescence (CL) system based on the oxidation of bromide by permanganate in sulfuric acid medium is introduced. The enhancing effect of silver nanoparticles (NPs), synthesized by chemical reduction method, on this reaction was studied. It was demonstrated that spherical silver nanoparticles with average size of 18nm had a most remarkable catalytic effect on this reaction. CL emission wavelengths and UV–vis spectra were used to characterize the system and propose a possible mechanism. Furthermore, it was found that captopril inhibits the action of NPs and decreases the intensity of CL. Based on this phenomenon, a new CL method was developed for the determination of captopril in the 3.0×10−10 to 1.0×10−7molL−1 concentration range with a detection limit (3s) of 0.12nmolL−1. The method was successfully applied to the determination of captopril in pharmaceutical formulations, human urine and serum samples.

Flow-injection spectrophotometric determination of captopril in pharmaceutical formulations using a new solid-phase reactor containing AgSCN immobilized in a polyurethane resin

A simple flow-injection analysis procedure was developed for determining captopril in pharmaceutical formulations employing a novel solid-phase reactor containing silver thiocyanate immobilized in a castor oil derivative polyurethane resin. The method was based on silver mercaptide formation between the captopril and Ag(I) in the solid-phase reactor. During such a reaction, the SCN- anion was released and reacted with Fe3+, which generated the FeSCN2+ complex that was continuously monitored at 480 nm. The analytical curve was linear in the captopril concentration range from 3.0 × 10-4 mol L-1 to 1.1 × 10-3 mol L-1 with a detection limit of 8.0 × 10-5 mol L-1. Recoveries between 97.5% and 103% and a relative standard deviation of 2% for a solution containing 6.0 × 10-4 mol L-1 captopril (n = 12) were obtained. The sample throughput was 40 h-1 and the results obtained for captopril in pharmaceutical formulations using this procedure and those obtained using a pharmacopoeia procedure were in agreement at a 95% confidence level.

Application of brominating agents and potassium dichromate for the spectrophotometric determination of captopril in pharmaceutical formulations

Three simple and sensitive spectrophotometric methods were developed for the estimation of captopril (CAPT) in pure form or in tablet formulations. The three methods are based on the reactivity of the thiol group. The first two methods (A and B) are based on the oxidation of CAPT by bromate/bromide mixture of known concentration in acid medium. In method A, the determination of the residual bromine is based on its ability to bleach the methylene blue dye and measuring the absorbance at 664 nm. Method B involves treating the unreacted bromine with a measured excess of iron(II) and the remaining iron(II) is complexed with 2,2 � -dipyridyl and the increase in absorbance is measured at 523 nm. Method C involves the addition of a known excess amount of potassium dichromate in acidic medium, followed by the estimation of unreacted amount of dichromate by reacting with excess of iron(II). The resulting iron(III) is complexed with thiocyanate and the absorbance is measured at 478 nm. In all the methods, the amount of oxidant reacted corresponds to the drug content. The different experimental parameters affecting the development and stability of the color product are carefully studied and optimized. After validation, the proposed methods were successfully applied to assay of CAPT in its commercial tablets. No interference was observed from common additives found in pharmaceutical preparations. The results were statistically compared with those of a reference method by applying Student's t- and F-test.

Flow Injection Spectrophotometric Determination of N-Acetylcysteine and Captopril Employing Prussian Blue Generation Reaction

A novel flow injection procedure to determine N-acetylcysteine and captopril in pharmaceutical formulations is proposed. The flow procedure developed was based on oxidation of the analytes by Fe(III) in acidic medium and subsequent reaction of the Fe(II) generated with excess hexacyanoferrate(III) to produce soluble Prussian blue (KFe[Fe(CN)6]) measured at 700 nm. Detection limits of 1.0 × 10−5 mol L−1 and 3.0 × 10−5 mol L−1 for N-acetylcysteine and captopril, respectively, were found. The sample throughput was 70 h−1 for both analytes and the results obtained were in agreement at a 95% confidence level with those obtained using reference methods.

Voltammetric Determination of Captopril Using Chlorpromazine as a Homogeneous Mediator

Chlorpromazine was used as a homogeneous electrocatalyst in the oxidation of captopril. The anodic peak current of chlorpromazine was increased substantially in the presence of low concentrations of captopril (pH 4). Cyclic voltammetry and chronoamperometry were used to study the kinetics of the catalytic electron transfer reaction. The values of electron transfer coefficient () and catalytic rate constant () were estimated to be 0.34 and , respectively. Linear sweep voltammetry was used for the determination of captopril in the presence of chlorpromazine. A linear calibration curve was obtained in the concentration range of captopril of 10.0–300.0 μM, with a limit of detection of 3.65 μM. The relative standard deviation (RSD%) for 5 replicate measurements of captopril (100 μM) was 1.96%. The method was applied to the determination of captopril in pharmaceutical formulations and blood serum samples with satisfactory results.

Flow-Injection Spectrophotometric Determination of Captopril Exploiting Silver Chloranilate Solid-Phase Reactor

A novel, simple, and rapid flow-injection method for the spectrophotometric determination of captopril in pharmaceutical products, using a solid-phase reactor with silver chloranilate (Ag2C6Cl2O4) immobilized in a polyester resin, is presented. This method explored the formation of an insoluble salt between Ag(I) and captopril in the solid-phase reactor, releasing chloranilate anion (). Then, this anion reacted with ferric ions to produce a complex, , which was monitored spectrophotometrically at 528 nm. The analytical curve was linear in the captopril concentration range from 1.0 × 10−5 to 5.0 × 10−4 mol l−1 with a detection limit of 8.0 × 10−6 mol l−1. The relative standard deviation (RSD) was 0.35% (n = 10) for a solution of 3.0 × 10−4 mol l−1 captopril solution, and an analytical frequency of 70 h−1 was obtained. The effects of excipients frequently found with captopril in pharmaceutical formulations, such as lactose, microcrystalline cellulose, starch, and magnesium stearate, were evaluated using the proposed flow-injection method. None of these substances caused significative interference in the proposed method. The method was successfully applied to the determination of captopril in pharmaceutical products, and the results were compared with results obtained using a potentiometric method.

Determinação condutométrica de captopril em formulações farmacêuticas utilizando sulfato de cobre(II) como titulante

CONDUCTOMETRIC DETERMINATION OF CAPTOPRIL IN PHARMACEUTICAL FORMULATIONS USING COPPER(II) SULPHATE AS TITRANT. A simple and rapid conductometric method for captopril determination using copper(II) sulphate solution as titrant was developed. The method was based on the chemical reaction between captopril and Cu(II) ions yielding a precipitate. The conductance of the solution was monitored as a function of the added volume of titrant. The method was applied with success for captopril determination in three pharmaceutical formulations. The relative standard deviation for six successive measurements was smaller than 0.5%. Recovery values from three samples, ranging from 97.7 to 103%, were obtained.

Flow-Injection spectrophotometric system for captopril determination in pharmaceuticals

A simple, accurate and precise flow-injection spectrophotometric procedure is reported for the determination of captopril in pharmaceutical formulations. In this procedure, captopril was oxidized by iron(III) and the iron(II) produced was spectrophotometrically monitored as iron(II)-1,10-phenantroline complex at 540 nm. The analytical curve for captopril was linear in the concentration range from 1.0 × 10-5 to 8.0 × 10-4 mol L-1 with a detection limit of 5.0 × 10-6 mol L-1. The recovery of this analyte in five samples ranged from 98.5 to 102.4%. The analytical frequency was sixty determinations per hour and the RSD was less than 0.2% for a captopril concentration of 4.0 × 10-4 mol L-1 (n = 10). A paired t-test showed that all results obtained for captopril in commercial formulations using the proposed flow injection procedure and a potentiometric procedure agreed at the 95% confidence level.

Validation of simultaneous volumetric and spectrophotometric methods for the determination of captopril in pharmaceutical formulations

Simple, sensitive and economical simultaneous volumetric and spectrophotometric methods for the determination of captopril have been developed. The methods were based on the reaction of captopril with potassium iodate in HCl medium. Amaranth was used as indicator to detect the end-point of the titration in aqueous layer. The iodine formed during the titration was extracted into CCl 4 and subsequently determined spectrophotometrically at 510 nm. The Beer's law was obeyed in the concentration range of 120–520 μg ml −1. Rigorous statistical analyses were performed for the validation of the proposed methods. The proposed methods were successfully applied to the determination of captopril in dosage forms. Comparison of the means of the proposed procedures with those of reference methods using point and interval hypothesis tests showed no statistically significant difference.